I would like to recommend Psychonauts (http://www.psychonauts.com/). It won some prizes last year and got some great reviews (http://www.gamespot.com/pc/action/psychonauts/review.html), but I only got to play it today. Real nice, haven't had such fun since the days of Commander Keen 4 (http://www.commander-keen.com/secret-of-the-oracle.php) (or was it CK5 (http://www.commander-keen.com/the-armageddon-machine.php)?)!
Have a go, and don't look into MY emotinal baggage :D
[here's a link to the metascore (http://www.metacritic.com/games/platforms/pc/psychonauts?q=psychonauts)]
I bought it a while back over Steam because I needed something to play until Burning Crusade came out (it was early January, there was nothing new out that I wanted, and due to the release delay of BC I had got a bit bored of WoW, if only because all of my mates who'd been playing it longer than me had stopped playing until BC came out).
It is indeed awesome, although I never actually completed it as the final set of levels had this one single jumping 'puzzle' that i just couldn't get right, and after about 30 mins of trying per attempt, 1 attempt per day for about 3 or 4 days, I got really fed up and uninstalled the game.